This paper presents the development of the rigid block version of discontinuous deformation analysis and its preliminary application in rockfall simulation. Modifications, including the reduction of the error due to large rigid body rotation by using post-correction at each time step of calculation and the incorporation of mass proportional damping to account for energy losses, are made to meet the requirement for large block translation as well as rotation. To improve the program efficiency, rigid body displacement function and preconditioned conjugate gradient solver are adopted. The results obtained show that the newly developed code, RIG-DDA, can appropriately and efficiently model various modes of rockfall movement and predict the trajectory of falling rock debris, which is helpful in the design of protection measures.